l-r: Earl Snell and James Currington inspect the tomatoes growing in Snell's hoop house.

On a recent December day, Earl and Clarisse Snell, of Skipperville, Alabama, proudly showed off the summer squash and tomatoes they were still growing at the start of winter thanks to the seasonal high tunnel they built earlier in the year. Also called hoop houses, seasonal high tunnels look a lot like greenhouses but require no artificial energy source—all they need is natural sunlight to grow vegetables, fruits, and other crops. Read more »